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Satellite Free Drop Generation for Large Wavelength to Nozzle Diameter Ratios

IP.com Disclosure Number: IPCOM000083682D
Original Publication Date: 1975-Jul-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Helinski, EF: AUTHOR [+2]

Abstract

Satellite-free drop generation is difficult to obtain where the ratio of drop wavelength to nozzle diameter is high (i.e., lambda/D>10), yet relatively long wavelengths are required to maintain drop stability and to minimize fringing in a magnetic ink jet printer. When high resolution (small spot size) printing is required, high lambda/D ratios are necessary to minimize fringing and yet maintain a small spot size.

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Satellite Free Drop Generation for Large Wavelength to Nozzle Diameter Ratios

Satellite-free drop generation is difficult to obtain where the ratio of drop wavelength to nozzle diameter is high (i.e., lambda/D>10), yet relatively long wavelengths are required to maintain drop stability and to minimize fringing in a magnetic ink jet printer. When high resolution (small spot size) printing is required, high lambda/D ratios are necessary to minimize fringing and yet maintain a small spot size.

The problem is solvable by generating magnetic ink drops of a size and spacing which produces a low ratio of wavelength-to-nozzle diameter, i.e., in the region in which satellites do not form. Groups of adjacent drops are then merged in flight, to produce the desired drop size and spacing for effective drop stability and control for printing.

As seen in the drawing, a pressurized supply of magnetic ink 10, such as a ferrofluid, is connected to a nozzle 11 which causes a magnetic ink filament 12 to be projected toward a relatively moving record medium 13. A magnetic exciter 14 is energized with high-frequency pulses, causing varicosities to be produced in the filament 12 and to ultimately break up into individual drops 15. The size and spacing of drops 15 is dependent on the diameter of the orifice of nozzle 11, the velocity of the fluid and the frequency of the excitation signal.

A magnetic transducer 16, located downstream from exciter 14 proximate the trajectory of drops 15,...